The regular US stock session runs from 9:30 a.m. to 4:00 p.m. ET, but trading does not stop at those times. Exchanges and alternative trading systems run sessions before the open and after the close, and a few venues already trade through the night. The rules in those sessions differ from the daytime market in ways that cost money if you miss them: which orders you can use, how far prices can move and how wide spreads get. This guide covers who can trade, the order rules, a worked spread-cost comparison and the status of overnight trading as of November 2026. For the full schedule of sessions, holidays and early closes, see stock market hours and holidays, and for the rest of the basics, the stocks hub.
When are the pre-market and after-hours sessions?
Nasdaq, NYSE Arca, Cboe EDGX and several other venues open for pre-market trading at 4:00 a.m. ET and run after-hours trading from 4:00 to 8:00 p.m. ET. Your broker decides which part of those windows it offers, and some firms start later or stop earlier than the exchanges, so the session you can trade in is set by your firm rather than by the venue.
| Session | Hours (ET) | Where it trades | Share of US share volume |
|---|---|---|---|
| Overnight | 8:00 p.m. to 4:00 a.m. | Alternative trading systems today; exchanges planned from December 2026 | 0.9% in August 2026 |
| Pre-market | 4:00 a.m. to 9:30 a.m. | Exchanges and alternative trading systems | 7.1% in Q2 2025 |
| Regular | 9:30 a.m. to 4:00 p.m. | Every exchange and off-exchange venue | About 88% in Q2 2025 |
| After-hours | 4:00 p.m. to 8:00 p.m. | Exchanges and alternative trading systems | 4.9% in Q2 2025 |
The quarterly shares come from NYSE research and the overnight figure from SEC staff. Measured in dollars rather than shares, off-hours trading was a smaller 8.6% in the second quarter of 2025, partly because cheap shares make up a big part of early trading: Cboe reported that sub-dollar securities grew to almost 20% of pre-market volume by the end of 2024, and ETFs such as QQQ to almost 25%. Individual investors drive much of it. On NYSE Arca, almost 8 of every 10 non-S&P 500 shares traded pre-market had a retail investor on one side, compared with 4 of 10 for S&P 500 stocks.
Who can trade outside regular hours?
Anyone whose broker offers it, once the firm has delivered the risk disclosure FINRA requires; exchanges deal only with member firms, so individuals trade through a broker. FINRA Rule 2265 bars a firm from letting a customer trade in extended hours until it has given that customer a risk disclosure statement, and a firm that offers online trading must also post the statement on its website. The disclosure has to cover six risks: lower liquidity, higher volatility, changing prices, unlinked markets, an exaggerated effect from news announcements and wider spreads. Expect to accept it before your firm switches extended-hours trading on.
Venues also limit who connects directly. NYSE Arca's extended sessions are open only to its member broker-dealers, and everyone else reaches them through a member. Brokers then choose which securities they make available, and Investor.gov notes that some stocks may not trade at all in extended hours. The order types a venue accepts can also differ from its daytime rules, which matters more than anything else on the order screen.
Why do brokers accept only limit orders in extended hours?
Thin, jumpy quotes could fill a market order far from the last price, so many firms accept only limit orders outside regular hours. Investor.gov describes the limit-only rule as protection from unexpectedly bad prices: a limit order executes only at its price or better, and if the market moves away, it simply does not execute. The exchanges preparing overnight sessions have built the same idea into their rules. Nasdaq's approved Night Session permits only limit orders, rejects unpriced orders such as market orders, and applies limit order protection to what is entered. Cboe EDGX's overnight session will not accept pegged orders without a cap price and will take only IOC, FOK, day, GTC, GTX and GTD time-in-force instructions.
Timing instructions need the same care. A regular day order expires at 4 p.m. ET and does not roll into the after-hours session, so an order meant for extended hours has to be marked for it, and firms label those instructions in different ways. Investor.gov suggests asking whether unfilled extended-hours orders are canceled at the end of the session or entered automatically when regular trading opens. Stop and trailing stop orders held by a broker may trigger only in the regular session, so check before counting on one overnight; stock order types shows how each order fills when a price gaps.
Order handling differs as well. The Order Protection Rule, which during regular hours stops a trade from executing at a worse price than a quote displayed on another exchange, does not apply in extended sessions, as Cboe points out, and consolidated quote data may not be readily available. Investor.gov suggests asking where your firm sends extended-hours orders and whether it seeks the best displayed price.
How much wider are spreads after hours?
Often several times wider, because fewer market makers are quoting; for less-traded securities, the gap between bid and ask can be many times its daytime size. Measurements vary with the stock, the venue and the period. A study of Nasdaq trading in 2000, published in the Journal of Finance, found quoted and effective spreads more than three times their daytime level after the close and more than four times before the open. In a 2025 study of one overnight trading system, BlackRock found that spreads on its most actively traded iShares ETFs averaged nearly 10 times their regular-hours level, and it had seen spreads 30 times wider on less-traded funds. Trading also bunches into a few names, so quotes in the rest are thinner still: SEC staff found that in August 2026 the 100 most active overnight stocks made up 82.0% of overnight share volume, against 34.0% in regular hours.
Worked example: Round-trip spread cost on 200 shares of a $40 stock
Regular session: the stock is quoted at $39.99 bid and $40.00 ask, a 1-cent spread.
- Buy 200 shares at $40.00, then sell 200 at $39.99: 200 × $0.01 = $2.00
After hours, the same stock is quoted at $39.85 bid and $40.10 ask, a 25-cent spread.
- Buy 200 shares at $40.10, then sell 200 at $39.85: 200 × $0.25 = $50.00, which is 25 times the regular-session cost
- If only 100 shares are offered at $40.10 and the next offer is $40.25, a buy limit at $40.25 fills the second 100 there, adding 100 × $0.15 = $15.00
- Total: $50.00 + $15.00 = $65.00, or about 0.81% of the $8,000 position, against 0.025% in the regular session
These quotes are illustrative; real after-hours spreads change from stock to stock and minute to minute. Look at the current quote before entering an extended-hours order, as shown on our stock pages for heavily traded funds such as SPY, and price the limit with the spread in mind.
| Feature | Regular session | Pre-market and after-hours |
|---|---|---|
| Hours (ET) | 9:30 a.m. to 4:00 p.m. | From as early as 4:00 a.m. to 9:30 a.m., and 4:00 to 8:00 p.m. |
| Orders accepted | Market, limit, stop and others | Limit orders only at many brokers |
| Limit up-limit down bands | Yes | No |
| Typical spread on a heavily traded stock | A penny or two | Several times wider, and far wider in thin names |
| Risk disclosure required first | No | Yes, under FINRA Rule 2265 |
| Share of US share volume | About 88% in Q2 2025 | 12.0% in Q2 2025 |
Why do prices swing on news outside regular hours?
Companies often release earnings before the open or after the close, when few traders are active, so a handful of orders can move the price sharply. Investor.gov lists news announcements as their own extended-hours risk for that reason, and how to read an earnings report covers what those releases contain. Three things make these moves harder to trade.
First, the guardrails are mostly absent. Limit up-limit down bands operate only from 9:30 a.m. to 4:00 p.m. ET, and the consolidated tape plans confirm that no bands apply from 4:00 to 9:30 a.m. or from 4:00 to 8:00 p.m. For the planned overnight session, the plans propose static price bands, subject to SEC approval. Second, extended-hours prices may not last: Investor.gov warns that they may not reflect where the stock trades at the end of the regular session or when it opens the next morning. Third, the other side of a news-driven trade is often a professional trader with more information, a point the same bulletin makes.
Is 24-hour stock trading available yet?
Not on US exchanges yet: overnight trading runs today on a handful of alternative trading systems, while four exchanges prepare sessions from 9 p.m. to 4 a.m. ET. Exchanges are scheduled to open those sessions on December 6, 2026, pending readiness of the consolidated data feeds and any remaining SEC rule changes. The model is 23 hours a day, five days a week, rather than true round-the-clock trading of the kind crypto markets offer. The consolidated data feeds plan to run from 9 p.m. ET Sunday to 8 p.m. ET Friday, pausing from 8 to 9 p.m. ET Monday through Thursday for maintenance, and DTCC's clearing arm began clearing 24 hours a day, five days a week on June 28, 2026.
| Venue | Status on November 2, 2026 | Overnight session (ET) |
|---|---|---|
| Nasdaq | SEC approved its 23-hour plan on April 10, 2026 | Night Session 9 p.m. to 4 a.m., Sunday to Thursday nights |
| Cboe EDGX | Expanding to 23-hour trading from December 6, 2026 | 9 p.m. to 4 a.m., with December 7 as the first trade date |
| NYSE Arca | SEC approved a 22-hour day in February 2025; plans overnight trading from December 6, 2026, subject to remaining approvals | 9 p.m. to 4 a.m., taking orders from 8:59 p.m. |
| 24X National Exchange | Trades from 4 a.m. to 8 p.m. now; overnight targeted for December 6, 2026 | 9 p.m. to 4 a.m., with SEC relief to start on January 24, 2027 if the data feeds are not ready |
| Alternative trading systems | Operating now | Roughly 8 p.m. to 4 a.m. |
Overnight activity is small but growing fast. SEC staff counted 144.6 million shares a day in the overnight session in August 2026, 0.9% of all share volume in exchange-listed stocks and 359% more than a year earlier, spread across an average of 4,208 stocks a night. One quirk of the current setup: alternative-trading-system trades between 8 p.m. and midnight on Sunday are reported to FINRA but withheld from the public tape, because Sunday counts as a non-business day.
The new sessions carry risks of their own, which Nasdaq's rules require brokers to disclose to customers before they trade at night. The stock's primary listing market may be closed, protections such as single-stock volatility controls may be limited, there are fewer fallback options if a system fails, and other parts of the market's plumbing may be shut, which can delay settlement. Trades between 9 p.m. and midnight will carry the next trading day's trade date, and settlement follows one business day after that date.
What are the risks of extended-hours trading?
Thin liquidity is the root risk: fewer orders mean wider spreads, partial or missed fills, sharper swings and prices that may not last into the next session.
- Cost. The spread is the main trading cost outside regular hours, and as the worked example shows, it can multiply the cost of a round trip many times over.
- No fill, or part of one. A limit order protects the price but may sit unfilled while the stock moves away.
- Unlinked markets. Venues are not tied together the way they are during the day, so the price on one may be worse than on another at the same moment.
- Missing guardrails. The price bands and trading pauses that apply in the regular session do not apply in pre-market and after-hours trading.
- Orders that outlive your intent. Depending on the firm's rules and the instruction you chose, an order may carry from an extended session into the regular one, or the other way.
- Professional competition. Many extended-hours traders are professionals with more information than individual investors.
- Overnight specifics. In the new overnight sessions the listing market may be closed, fixes for system problems may be limited, and infrastructure closures can delay settlement.
Long-term investors can do all their buying in the regular session, where spreads are tightest; types of investment risk puts liquidity risk in the wider context, and how to buy stocks walks through the order screen step by step.